When soft tissue tears away from bone, reattachment becomes necessary. Various devices, including sutures alone, screws, staples, wedges, and plugs have been used in the prior art to secure soft tissue to bone. Recently, various types of threaded suture anchors have been developed for this purpose. Some threaded suture anchors are designed to be inserted into a pre-drilled hole. Other suture anchors are self-tapping.
Problems can arise if the structure for attaching the suture fails, allowing the suture to become detached from the anchor. Also, the suture often is exposed to abrasion or cutting by sharp or rough areas along the walls of the bone canal into which the anchor is inserted.
Further, the prior art suture anchors having eyelets extending from the proximal ends require countersinking of the eyelet below the bone surface to avoid having the patient's tissue abrade against the exposed eyelet. As a result, suture attached to the eyelet is vulnerable to abrasion by the bony rim of the countersunk hole into which the suture anchor is installed. In addition, in biodegradable prior art devices, the eyelet can degrade rapidly, causing the suture to become detached from the anchor prematurely.
Accordingly, a need exists for a threaded suture anchor to which suture is secured effectively so as to prevent detachment of the suture and eliminate anchor “pull back.” In addition, a need exists for suture anchors having eyelets that will not abrade tissue and do not require countersinking. Suture anchors having a small core diameter providing maximum pullout strength even in soft bone and maximum suture fixation strength are also needed.